Turbine blade and mounting



2 Sheets-Sheet 1 A. J. PHELAN TAL TURBINE BLADE AND MOUNTING Filed Aprile, 1945 Nov. 4, 1947.

NOV. 4, 1947. A, PHELAN ETAL 2,430,140

TURBINE BLADE AND MOUNTING Filed April e, 1945 2 .she'ets-sheet 2 arecustomarily mounted Patented Nov. 4, 1947 2,430,140 l TURBIN E BLADE ANDMOUNTING Arthur J. Phelan,

Walden, Long Be Paciiic Palisades, ach, and Neill F.

Charles 0. McGaii'ey,

Inglewood, Calif., assignors to Northrop-Hendy Company, Hawthorne,Calif., a corporation ot Californi Application April 6, 1945, Serial No.586,964 2 Claims. (Cl. 253-77) u; invention relates to turbines and morevparticularly to the blades and the manner of mounting the same to aturbine.

Turbines, and

constructed with the rotor or stator frame of gas turbines inparticular, are a. minimum of clearance between the rows of blades onthe rotor frame and those on the stator frame. The individual blades inundercut grooves formed in the turbine components, such as the rotor andstator frames. The assembling of such blades presents a rather tediousoperation, in that they must be assembled individually by inserting eachblade at an open point in the undercut groove and then urging it alongthe groove until the blade reaches its ilnal position in the assemsuchblades in time are loosened at their base sections where anchored to therotor or stator frame,

mounted.

Among the objects of our invention are:

(a) To provide novel and improved means of assembling rotor and statorblades in a turbine.

l wall of the lbase section (b) To provide novel and improved turbineades which will facilitate and improve the assembling of the same to arotor or stator frame oi' a turbine.

(c) To provide a novel and improvedl turbine blade assembly in which theblades are solidly anchored against the eii'ects of forces developedduring normal operation of a turbine.

(d) To provide a novel and improved turbine blade and anchoring meansfor simplifying the assembling and disassembling of the blades.

Additional objects of Qur invention will be brought out in the followingdescription of the same, taken in conjunction with the accompanyingdrawings wherein:

Fig. 1 is a fragmentary view in elevation depicting certain features ofour invention relating to the anchoring of the last blade to beassembled to the rotor frame of a turbine;

Fig. 2 is a view in section along the line 2-2 of Fig. 1 andillustrating the manner of assembling the last blade in position;

Fig. 3 is a view in section along the line 3 3 of Fig. 2;

Fig. 4 is a plan view of the shroud portion of Fig. l.

applicable to the mounting of the blades to the stator component of aturbine.

Each blade comprises a base section 'l.` The provided with locking pinreceiving grooves of substantially semi-circular crosssection and wherethe particular blade is o1' airfoil cross-section, the groove 9 in theend of the base section is so dimensioned that one of the side wallscoincides with or lies near a 1ongitudi nal line I5 through the centerof gravity of the blade, and that particular side Wall of the groovewill have more locking pin grooves than the opposite side wall. In thespecic embodiment of our invention as disclosed in Fig. 1, a pair oi'locking grooves l1 and I9 are formed in one side groove 9 Whereas only asingle locking pin groove 2| is provided in the opposing sidewall. 4

The rotor frame 21 is provided with a peripheral mounting rib 29 fortheblades, this rib being bounded on either side by a channel 3| and 33.The dimensions of the rib 29 and mounting channels 3| and 33 are such asto enable the blades to snugly lit .over and straddle the rib with thelegs and |3 entering and closely tting into the mounting channels 3| and33 respectively. The rib is provided in its side walls with lockingpmgrooves, 35, 31 and 39, complementary to the locking pin grooves, I1, I9and 2| in the base section of the blade.

In assembling a blade, it is applied radially into straddling engagementwith the rib at the position it is to occupy on the rotor frame. Thecomplementary locking pin grooves 'then form cylindrical passages forthe reception of locking pins 4| which when driven into these passages,serve to lock the blade to the rib and prevent its removal therefrom."Ihe pins 4| are preferably of a length equal to the length of the basesection 1, with their ends tapered or rounded to facilitate insertioninto position, and are arcuate in form to conform to the curvature ofthe passages provided by the locking pin grooves.

The above discussed procedure for assembling a blade to the rotor framewill be repeated in connection with each blade except the last blade tobe mounted on that particular rib. In assembling this last blade in therow, to the rotor frame, a departure from the above described method ofassembling blades must be resorted to.

In this connection, a side opening 43 is provided at the junction of thebase section of the last blade and base section of the preceding blade,such opening being the grooves 35 and 31 in the mounting rib 29. Acorresponding opening 45 is also provided on the opposite side of thebase sections of the last blade and preceding blade. Through theseopenings, short anchor pins 41 preferably having beveled or roundededges, are inserted one at a time and then driven laterally into thelocking pin passages of the last blade by means of a sharp wedgeshapedtool, until such passages are filled, at which time snugly iitting plugs49 and 5l, respectively, are driven into the openings 43 and 45 andretained therein by peening over the adjacent metal of the base sectionsof both the last blade and the preceding blade.

It will be obvious from the above described means and method lofassembling blades, that such means and method can be employed in theassembling of blades having free peripheral ends. In many cases,however, it is desirable that the peripheral ends of the blades be tiedtogether, as for example, to form a shroud. One such method involves thetermination of each blade in a shroud segment 53 which is adapted toabut the shroud segment of the adjacent blade on either side thereofduring assembling, and tying the shroud segments together by anchoringpins 55 therein which bridge the abutting ends 4of the segments.

Adapting this general procedure to the assembling of the last blade inaccordance with the present invention, we provide anchoring pin holes 51in the ends of the shroud segment to a depth slightly greater than thelength of the anchoring pins to be employed, and lateral connectingopenings 59 at the inner ends of such anchoring pin holes.

In the opposing ends of the shroud segments of the adjacent blades, weprovide correspondingly located anchoring pin holes 6| to a depthapproximately equal to half the length of the anchororing pins tobeutilized.

Prior to assembling the last blade to the mountof a depth suiiicient toexpose A ing rib, anchoring pins are inserted into the shroud segmentthereof to a depth which will leave the pins iiush with the ends of theshroud segment. yAfter the last blade has been assembled to the mountingrib as previously described, fluid under high pressure is forced intothe lateral connecting openings 59 to drive the shroud anchoring pinsinto the shroud segments of the adjacent blades.

To provide relief for trapped air in the anchoring pin holes of thesegments of the adjacent blades, as well as for such fluid as may escapepast the pins during the application of the high pressure fluid thereto,we provide leak openings E3 through the side edges of the adjacentshroud segments and connecting with the inner ends of ,the shroudanchoring pin holes in such segments.

Following the driving of the shroud anchoring pins to their nalpositions, a ball pointed tool is applied to collapse or constrict thehole behind each pin just suiliciently to prevent the pin from workingout. This leaves slight impressions in the outer face of the shroudsegment of the last blade, but this is removed in the final machiningoperation on the shroud.

While we have shown only one mounting rib in the drawing, it isunderstood that there will be as many mounting ribs as there are rows ofblades on the rotor. and that these rows will be interspersed with rowsof blades of the associated stator of the machine.

In the event that the blades are of the type wherein the center ofgravity lies on the longitudinal axis of the blade, the number oflocking pins on either side of the mounting ribs will preferably be thesame, and in most cases need not exceed one.

Our invention results in very solidly anchored blades. The constructionis such as to discourage rocking of the blades, thereby'prolonging thelife of a machine beyond what might be expected for prior constructions,wherein the blades are mounted in undercut grooves. As also previouslypointed out, the assembling of the blades has been considerablysimpliiied by the fact that they are applied radially, and therefore can'be assembled directly to their positions on the frame.

Thus, it is apparent that our` invention fulfills the objects thereof asoutlined previously7 and while we have disclosed a preferred embodimentof our invention, it is apparent that the same may be subject to changeor alteration without departing from the principles thereof, and weaccordingly do not desire to be limited in our protection to the specicdetails disclosed, except as may be necessitated by the appended claims.

We claim:

1. In combination, a circular blade carrying component of a turbine orthe like, a peripheral rib encircling said component and having parallelflat side walls with semicylindrical locking pin grooves in the sidewalls thereof, a plurality of blades each including a base sectionhaving a rib engageable groove in the bottom end thereof andcomplementary semi-cylindrical locking pin grooves in the side walls ofsaid rib engageable groove, said blades being mounted in straddlingengagement with said rib, and a plurality of cylindrical locking pins inthe passages formed by said complementary locking pin grooves.

2. In combination, a circular blade carrying component of a turbineor'the like, having a peripheral rim section, a. turbine blade having aI6 base section, one of said sections having a rathe passages formed bysaid complementary lo grooves.

ARTHURJ. PHEIAN. CHARLES o. WALDEN. NEILL F. MCGAFFEY.

REFERENCES CITED The following references are of record in the le ofthis patent:

Number l UNITED STATES PATENTS I Name Date Guy Nov. 3o, 1920 Hall Apr,6, 1943 Rydmark Apr. 20. 1943 Sweet Oct. 11, 1910 Wessel July 17, 1928Noack Apr. 28, 1936 Bartch Nov, 17, 1942

